The present invention relates to an apparatus and a method for performing a simulated image-guided medical procedure and, more particularly, but not exclusively to performing a simulated image-guided procedure according to a three-dimensional (3D) model of an organ that is based on a 3D medical image.
Medical imaging is generally recognized as important for diagnosis and patient care with the goal of improving treatment outcomes. In recent years, medical imaging has experienced an explosive growth due to advances in imaging modalities such as x-rays, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. These modalities provide noninvasive methods for studying internal organs in vivo, but the amount of data is relatively large and when presented as two dimensional (2D) images, it generally requires an anatomist/radiology specialist for interpretation. Unfortunately, the cost incurred in manual interpretation of this data is prohibitive for routine data analysis. The 2D slices can be combined to generate a 3-D volumetric model.
Such medical imaging systems allow the performance of minimally invasive therapeutic procedures. These procedures are typically carried out in a CathLab, where a physician wishes to assess the functions of internal organ such as the heart and coronary artery or to perform procedures such as coronary angioplasty.
Most radiology yields recorded images such as 2D X-ray films or 3D medical images such as CT and MRI scans. Mild dosage interactively controlled X-Ray, also known as fluoroscopy, allows a physician to monitor actively an operation at progress. Interventional radiology is the specialty in which the radiologist and cardiologists utilizes real time radiological images to perform therapeutic and diagnostic procedures. Interventional radiologists currently rely on the real-time fluoroscopic 2D images, available as analog video or digital information viewed on video monitors.
However, these procedures involve delicate and coordinated hand movements, spatially unrelated to the view on a video monitor of the remotely controlled surgical instruments. Depth perception is lacking on the flat video display and therefore it is not an easy task to learn to control the tools through the spatially arbitrary linkage. A mistake in this difficult environment can be dangerous. Therefore, a high level of skill is required, and a realistic training of these specialists is a complex task. In addition, usually there is no direct engagement of the depth perception of the radiologist, who must make assumptions about the patient's anatomy to deliver therapy and assess the results.
Medical simulators that can be used to train such medical specialists have significant potential in reducing healthcare costs through improved training, better pre-treatment planning, and more economic and rapid development of new medical devices. Hands-on experience becomes possible in training, before direct patient involvement that will carry a significant risk.
Image-guided procedures, such as vascular catheterization, angioplasty, and stent placement, are specially suited for simulation because they typically place the physician at-a-distance from the operative site manipulating surgical instruments and viewing the procedures on video monitors.
For example, U.S. Pat. No. 6,062,866 published on May 16, 2000 describes a medical model for teaching and demonstrating invasive medical procedures such as angioplasty. The model is a plastic, transparent three-dimensional, anatomically correct representation of at least a portion of the vascular system and in a preferred embodiment would include the aorta, coronary artery, subclavian arteries, pulmonary artery and renal arteries each defining a passageway or lumen. An access port is provided so that actual medical devices, such as a guide and catheter may be inserted to the location-simulated blockage. Fluid may also be introduced to simulate realistically in vivo conditions. Simulated heart chambers of similar construction may also be attached to the aortic valve to enhance further the representation of invasive procedures.
More complex simulation systems that provide more accurate, linked visual and tactile feedback during the training is disclosed in U.S. patent application No. 2003/0069719 published Apr. 10, 2003 that describes an interface device and method for interfacing instruments to a vascular access simulation system serve to interface peripherals in the form of mock or actual medical instruments to the simulation system to enable simulation of medical procedures. The interface device includes a catheter unit assembly for receiving a catheter needle assembly, and a skin traction mechanism to simulate placing skin in traction or manipulating other anatomical sites for performing a medical procedure. The catheter needle assembly and skin traction mechanism are manipulated by a user during a medical procedure. The catheter unit assembly includes a base, a housing, a bearing assembly and a shaft that receives the catheter needle assembly. The bearing assembly enables translation of the catheter needle assembly, and includes bearings that enable the shaft to translate in accordance with manipulation of the catheter needle assembly. The shaft typically includes an encoder to measure translational motion of a needle of the catheter needle assembly, while the interface device further includes encoders to measure manipulation of the catheter needle assembly in various degrees of freedom and the skin traction mechanism. The simulation system receives measurements from the interface device encoders and updates the simulation and display, while providing control signals to the force feedback device to enable application of force feedback to the catheter needle assembly.
Another example for a simulating system that is designed to simulate an image guiding procedure according to a predefined and fixed module is disclosed in U.S. Pat. No. 6,538,634 published on Mar. 25, 2003.
These simulation systems and other known simulation systems are based on predefined models, which are acquired and enhanced before the systems become operational or during a maintenance thereof, such as updating the system. Usually, a library that comprises virtual models which are stored in a related database is connected to the simulation system. During the operational mode, the system simulates an image-guided procedure according to one of the virtual models that has been selected by the system user.
Though such systems allow physicians and trainees to simulate image-guided procedures, the simulated image-guided procedures are modeled according to predefined or randomly changed models of an organ, a human body system, or a section thereof. As such, the physician or the trainee is trained using a model of a virtual organ that is not identical to the organ that he or she is about to perform an operative image-guided procedure on.
Moreover, when a virtual model is used, the simulation system cannot be used for accurately simulating an operation that has been performed on a real patient. Therefore, the currently used simulation systems cannot be used for going back over an operation that went wrong or for didactic purposes.
There is thus a widely recognized need for, and it would be highly advantageous to have, a system for simulating image-guided procedures, devoid of the above limitations, that can simulate in a more realistic manner the image-guided procedure that the physician is about to perform.